Patent GB-568514-A (GB)
Title: Marine-vessel steering mechanism
IPC: B63H25/28
Filed: 1943-07-19
Abstract: 568,514. Hydraulic transmission of power. WEBSTER-BRINKLEY CO. July 19, 1943, No. 11708. Convention date, July 20, 1942. [Class 69 (ii)] [Also in Group XXXIII] Ship steering gear comprises two independent hydraulic systems each including a source of power connected to a motor, the two motors normally acting in unison to swing the rudder, a connection between the two systems, whereby starting of either power source automatically couples it to both motors, and means for producing a hydraulic lock in the pipes connected to the motor cylinder when the gear is inoperative. In the form shown in Figs. 1 and 2, the rudder post 16 is connected by arms 18, 18<1> to hydraulic rams 20, 21 working in opposed cylinders AA<1>, BB<1> which are connected, through distributing valves 26-29 with a cross-over connection 111, to reversible variable delivery primary pumps 30, 31 governed by torque-equalizing units 36, 37. The latter are connected, through the distributing valves 41, 45 and 51, 55 of constant pressure pilot pumps 40, 50. The volumetric flow of the primary pumps 30, 31 is controlled by rods 77 connected by pivoted levers 73 to slidably mounted shafts 70, Figs. 13 and 14. The lower end of each of the latter is surrounded by a removable thimble 78 with a pinion 80 and a worm 81 which engages a threaded sleeve 82 with a pinion 85. The pinions 80, 85 mesh with parallel racks 86, 87, each of which carries a piston 88 and a thrust disc 89 in cylinders 90-93, the cylinders 92, 93 housing springs 94. These springs are augmented by a torque-equalizing line consisting of an open-ended tube 95 working in an end bore 96 of the racks 86, 87 and fed by pipes 97-100 connected to the responsive pressure side of the related primary pump 30 or 31. The distributing valves 26-29 each comprise two chambers 101, 102, Fig. 3, connected respectively with the ram cylinders and the primary pumps and communicating by spring-controlled valves 103, 104. The valve 104 carries a piston 1041 in a cylinder with end and side parts connected respectively to a pilot valve and to a cylinder of a torqueequalizing unit. The chambers 101 are connected together by double-chambered passages 112, 113 and 114, 115 in the cross-over 111, the two passages being interconnected by a pair of normally closed ducts with oppositelyacting relief valves, and each pair of chambers 112, 113 and 114, 115 are provided with normally open, manually set valves which may be closed to repair a distributing valve or one of the ram assemblies. For the same reason, the ram cylinders are connected by lines 120, 121 with normally closed valves 122, 123, and the pipe-lines therefrom with normally open valves 124-127. Each pilot valve includes a shuttle valve 62, Fig. 11, which is movable against the action of a spring 65 by a cam 66 operated by a Selsyn motor. This movement connects parts 59, 60 in the cylinder 58, and upon operation of, say, the pilot valve 41, pressure oil passes from pilot pump 40 to valve 27 to lift its piston 104<1> and valve 104. This allows the pressure oil to flow from valve 27 to the cylinder 90 of the torque-equalizing unit 36 and to move the rack 86 to start the pump 30 Prime fluid from ram cylinder A<1> is drawn through open valve 27, forced into valve 26 to open its valve 103, and then passes to the ram cylinder A. At the same time, prime fluid from ram cylinder B<1> is drawn through closed valve 29 and the cross-over 111 into valve 27 to emerge with the prime fluid from ram cylinder A<1> and thence to the suction side of pump 30. As the ram cylinders A, Bare connected by valves 26, 28 and the cross-over 111, the rams 20, 21 move in unison, and are held by a hydraulic lock by spring-influenced retraction of the pilot valve 41 causing valve 104 to close and trap the prime fluid against circulation, at the same time the rod 77 cutting out the pump 30.